Wireless communication provides significant flexibility to computer users. By communicating wirelessly, computer users may simply create a network or may have network connectivity as they move their computers from place to place. In a typical wireless local area network (WLAN), a wireless client connects to an access point (AP), and communication is enabled between the client and a network.
An AP is a piece of equipment that allows devices to connect to a network. Access points, for example, are used to allow wireless clients to connect to a wired network, enabling the wireless clients to use devices connected to the wired network. APs may be self-contained hardware devices. Alternatively, computing devices (e.g., laptops) can be adapted to act as APs through the use of software. Such software-based access points or “soft APs” may allow a wireless client to access services not only on a network to which the computing device is connected but also on the computing device itself.
Access points operate according to protocols that enable client devices to form network connections. Wireless access points frequently advertise their presence by broadcasting beacons at regular intervals. Each beacon frame may carry such information as the beacon interval, timestamp, service set identifier (SSID), supported data rates, and other pertinent data regarding the access point. The SSID identifies a specific network for which access is provided by the access point. Though, not all of this information may be broadcast in every scenario. For example, some access points may opt to disable the SSID from being broadcast in beacon frames to reduce security issues.
In addition to enabling a client device to find an access point, the periodic beacons can synchronize operation of client devices once they are associated with the network. For example, a beacon signal may indicate whether there are messages waiting for the client at the AP. Such a protocol allows more efficient operation of a client because it only needs to monitor for incoming messages at periodic beacon intervals and following receipt of beacons that indicate the access point has buffered messages for the client.